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Lignoscripta atroalba B. D. Ryan & T. H. Nash
Family: Trapeliaceae
Lignoscripta atroalba image
Bruce Ryan  
Life habit: lichenized Thallus: at least partly superficial, rimose to verruculose areoles: 0.3-0.7 mm across, becoming rimosely divided into smaller, +convex subunits surface: creamy white goniocysts: few or absent soralia: absent or present, elongated and immersed in cracks in the wood, slightly more yellowish than thallus; soredia: granular, photobiont: primary one a chlorococcoid green alga, secondary one absent Apothecia: common, immersed (disc flush with thallus) or slightly raised, 0.5-1.5 x 0.1-0.3 mm, parallel to irregularly arranged, ellipsoid to fusiform, becoming fusiform to elongate-fusiform or linear and aculeate disc: open, plane, pure black, epruinose, white within exciple: white pruinose, often conspicuous, level with disc or slightly raised; parathecium: brown-black, N+ dark orangish red epihymenium: non-granular, with pigment confined to paraphyses tips, green-black, N+ red; paraphyses: filiform (c. 1 µm wide), +loosely coherent, the tips clavate to capitate, 3-5 µm wide hymenium: hyaline, c. 100 µm high, I+ deep blue subhymenium: indistinctly delimited hypothecium: pale, tinged yellow-gray; hyphae: conglutinate, unoriented, narrow, with short cells asci: narrowly clavate, c. 85 x 17 µm, I+ pale blue, without differentiated tholus, 8-spored (with the spores uniseriate to irregularly biseriate) ascospores: hyaline, simple, ellipsoid to fusiform or broadly ellipsoid, 12.5-17(-22) x 10-12 µm, I-, without a thickened epispore Pycnidia: not infrequent, immersed, black; walls: green, N+ red conidia: bacilliform, c. 5 µm long Spot tests: apothecia and thallus K-, C-, KC-, P- Secondary metabolites: none detected. Substrate and ecology: on old wood (e.g., juniper), usually in pinyon-juniper communities, at moderate to high elevation (to 3170 m in Utah) World distribution: southwestern North America (Arizona and Utah) Sonoran distribution: Arizona, 2250-2740 m. Notes: Lignoscripta is easily distinguished from Xylographa by its white pruinose apothecial margins, its pure black discs, its green-black (N+ red) paraphyses tips, its taller hymenium, its larger asci, spores over 10 um wide, its blue-green pycnidial wall, and its short, straight, bacilliform conidia. While the bacilliform conidia suggest that this species might be close to Ptychographa, it differs from that genus especially in its green pigmentation, pale hypothecium, and larger spores.